This sheet issue just never occurred in my RV, and "the salesman said" is a non-starter for me. RV makers who buy enough mattresses can get any size that "fits."
Donn is right...give the system time to post your message...patience.
Winnebago 2101DS TT & 2022 Chevy Silverado 1500 LTZ Z71, WindyNation 300 watt solar-Lossigy 200 AH Lithium battery. Prefer boondocking, USFS, COE, BLM, NPS, TVA, state camps. Bicyclist. 14 yr. Army -11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad